Drier



L. H. ZEUN March 10, 1936'.

DRIER 8 Sheets-Shet 1 Filed April 23, 1932 r-|lllIIlllllllllllllllllllllllllIIIIIIIIQIIIII||||||||III||||||"In" INVENTOR ATTORNEY 8 Sheets-:Sheet 2 11v VENTOR L. H. ZEUN DRIER FiledApril 23, 1932 March 10, 1936.

March 10, 1936. L. H. ZEUN 2,033,169

' DRIER I I Filed April 23, 1932 8 Sheets-Sheet 3 11v VENTOR A TTORNEYMarch 10, 1936. U 2,033,169

DRIER Filed April 23, 1932 8 Sheets-Sheet 4 MarchlO, 1936;

L. H. ZEUN DRIER 8 Sheets-Sheet 5 Filed April 23, 1952 A TTORNE y March10, 1936.

DRIER 8 Sheets-Sheet 6 Filed April 28, 1952 Ilnuv ull March 10, 1936.

L, H. ZEUN DRIER Filed April 28, 1952' oooococoonooooooooo0000000000000oooooooooaofloooooouoooo o uooooooooaoooocoon-00060000000000 INVENTORATTORNEY L. H.- ZEUN March 10, 1936.

DRIER 4 Filed April 28, 1952 8 Sheets-Sheet 8 fin. R Y 1 o 5 M W m MPatented Mar. 10,- 1936 Louis H. Zeun, Oatonsville, Md., assignor toJohn B. Adt Company, Baltimore, Md.

Application April 28,1932, Serial No. 607,984

3C1aims.

The present invention relates to an improved.

form of apparatus and method for drying various materials in bulk suchas tobacco and the like.

In the drying of certain and various kinds of 5 materials such astobacco and the like, it is extremely important during the drying periodto extract only a certain and predetermined quantity of the moisturefrom the material being dried.

It has been found with the present type of commercial rotary driers nowbeing used, particularly for the drying of tobacco and the like, thatthese driers do not maintain their temperature at the desired degree ofheat needed for a given condition of drying, are not economical in theirconsumption of fuel, are inemcient in their operation, in that too greator too small an amount of moisture is extracted from the material,particularly when tobacco is being dried, also it may be scorched,burned, or unevenly dried in certain portions in other instances, thuspartially if not wholly defeating the original purpose of such a drier.

The inefficient functioning of these machines may be fully appreciatedwhen it is known that the material to be dried is, as a rule, introducedoriginally to the drier in a substantially wet condition; when the sameenters the drier through V the feed hopper. For this reason it is found0 necessary to maintain a very high initial degree of heat at the teedend of the cylindrical drier.

As this material is conveyed through the slowly revolving cylinder bymeans of spiral flights fixed to the inner wall thereof, it is beingconstantly elevated and then dropped back to the bottom of the shellthrough the action of the revolving cylinder and its spiral flights.This progressive agitation of the material being dried causes eachparticle to repeatedly come into intimate contact 40 with the highlyheated wall of the cylinder shell. This together with the preheatedstream of drying air passing through the'cylinder creates a conditionwith tremendous possibilities for ineflicient operation, unless thesevarious heating or drying mediums are properly controlled. It may alsobe readily seen that as the material, such as tobacco, progressesthrough the machine and a greater portion of the moisture has beenextracted therefrom, it is not -necessary to maintain the same highdegree of heat at that portion .or

end of the machine where the material is partially dry and nearing thepoint of delivery'from the machine. For this purpose the applicant hasprovided at various positions along the length of the drier shell aplurality of independent co-operative heating units or furnaces havingmeans for controlling and maintaining a predetermined independent degreeof heat in each of said furnaces, thus enabling the application of theproper specific degree of heat at various points 5 along the drier shellto cope eiiiciently with the moisture content of the material at anygiven point in the dryer. V

For purposes of increasing the effectiveness of the drying function ofthecommercial type of drier on the market today it is well known thatpreheated air is introduced within and circulated through the shell orcylinder of the machine for purposes of allowing the same to interminglewith the material being dried, thus acting as auxiliary means forextracting the moisture content from the material. However unless thispreheated air is controlled as to its degree of heat, it will tend tocause the overheating of the drying chamber, when combining with theexternal heating means for the shell, and produce a dried material thatis indefinite as to its moisture content. With this in mind, it is animportant feature of the present invention to provide means forcontrolling the temperature of this preheated air, and in a manner thatis co-operative with the external heating furnaces for the drier shell.This co-operative control-feature for the heat, enables the drier toproduce material such as tobacco and the like having a predeterminedmoisture content.

Still another object of the present. invention is to provide a drier ofthe type described, having means for controlling the mean temperature ofboth the preheated air and external heating means of the drier' shell.

Another object of the invention is to provide means whereby either asingle or a plurality of heating furnaces may be used in a co-operativemanner for drying purposes, together. with the air preheated thereby, ina co-operative manner and each of said furnaces having means forcontrolling the heat therefrom in an independent manner.

Another object of the present invention is to provide means incombination. with the above described heating and drying furnaces,whereby the burners of the gas fired type maybe controlled manually forthe purpose of intensifying the heat, by moving the burners toward oraway from the drier shell for purposes of controlling the impinging ofthe flames therefroin'ag'ainst the shell.

Still another object of the present invention'is to provide meanswhereby'the temperature'of the waste gases from each of the abovedescribed furnaces may be controlled automatically and independently ofeach other.

Still another object of the present invention is to provide means forforce feeding preheated air at controlled temperatures through the driershell of the machine in predetermined quantities for the purpose of morereadily controlling the evaporation of moisture from the material beingdried.

Still another important feature of the present invention is theprovision of means for controlling the flow of gas to the gas burners ofthe drier heating furnaces, in that each heating unit or furnace hasmeans for automatically controlling the flow of gas to its respectiveburners, together with means for preventing the flow of gas through theburners when the pilot burner is not burning.

Another object of the present invention is to provide means. whereby apredetermined minimum and maximum flow of gas to each of the furnacesmay be had for the purpose of controlling the minimum and maximum sizeof the gas flame from each of their respective battery of gas burners.

Still another object of the present invention is to provide a drier ofthe type described having means whereby the moisture laden air carriedoil from the drier by means of a vapor discharge stack will not becomecondensed therein but be carried off into the atmosphere withoutprecipitation.

In the performance of the method of the invention, the wet or moistureladen material to be dried is placed within the rotary drying shell ofthe machine at the feed end, thence conveyed at a predetermined speedthrough the drier shell. During the passage of the material through thedrier shell, it is being constantly subjected to a predetermined degreeor degrees of controlled heat from the outside of the shell, while a'continuous blast of preheated air at a predetermined degree of heat ispassed through the shell and caused to intermingle with the moistureladen material, thence carrying off the moisture extracted from thematerial by its action to a vapor discharge stack, having means forintroducing this saturated or moisture laden air to the atmospherewithout precipitation.

In the accompanying drawings I have illustrated a drying apparatus ofthe rotary shell type, the same being an embodiment of my inventioninsofar as it relates to the apparatus and being capable of operation inthe performance of the method of the invention, the apparatus beingcontrolled for this purpose either automatically or by hand.

In the drawings,

Figure 1 is a fragmentary elevation of substan tially one half myimproved rotary drier disclosing the feed or left end of the machine;

Figure 2 is a similar view to Figure 1 of my improved rotary drierdisclosing the other half or discharge end of the machine;

Figure 3 is an end elevation of the feed end of my rotarydrier;

Figure 4 is an end elevation or view of the discharge end of my rotarydrier;

Figure 5 is a somewhat diagrammatic fragmentary sectional view of thedrier taken on the line 5-5 of Figure 3, illustrating the independentheating furnaces, direction and travel of the gases therefrom, and themethod of preheating the fresh air introduced to the drier shell;

Figure 6 is a fragmentary detail assembly view in elevation of one ofthe heat or gas controlling units;

Figure '7 is a fragmentaryend elevation of one of the heat or gascontrolling units, as shown in Figure 6;

Figure 8 is a fragmentary plan view of the heat or gas controlling unitshown in Figures 6 and '7;

Figure 9 is a sectional view of the line 99 of Figure 1, disclosing theshell and housing structure for preventing the ready escape of the heatfrom the drier housing at this point;

Figure 10 is a fragmentary sectional view of both the minimum andmaximum diaphragm gas flow control valves, taken substantially on theline .|l0 of Figure 8;

Figure 11 is a fragmentary sectional view of the safety pilot member,taken substantially on the line l|-ll of Figure 8; and,

Figure 12 is a fragmentary sectional view of the thermostatic gascontrol unit, taken on the line l2--l2 of Figure 2.

Referring to the drawings by numerals, each of which is representativeof the same or similar parts throughout the various figures, theinvention consists of a drier housing I having positioned therein arotatable cylindrical drier shell 2 in which the material to be dried isplaced.

For purposes of introducing the moist mate.- rial or wet material to thedrier shell 2 the same has positioned at its feed end 3 the feed hopper4 having a conduit or passage leading to within the drier shell 2. Thissame end of the machine is provided with means for rotating the driershell 2, in the form of reduction gearing 6, and drive pulley 7, whichin turn may receive its driving power through the belt 8 and the drivingpulley 9 mounted on the power shaft I0. Power shaft It) also carries andhas mounted thereon the drive pulley ll having a belt l2 for purposes ofdriving the blower fan member l5 by means of its drive pulley M. Thefunction of this blower fan member I5 is broadly for the purpose ofcreating a forced draft of fresh air through the drier shell member 2and will be more fully hereinafter described.

For purposes of rotatively mountingthe shell member 2 and for directlycarrying the weight thereof, the same is provided with supportingrollers It at the feed end of the drier and I! at the discharge end.These rollers in turn are carried by supporting brackets l8 and H! atthe feed and discharge ends of the drier respectively.

Referring particularly to Figure 5 of the drawings, it will be notedthat the inner portion of the cylindrical drier shell member 2 isprovided with a plurality of spiral flights 20 for the purpose ofenabling the constant agitation of the material to be dried during itsprogress through the drier. These flights through the revolutions of thecylinder constantly elevate and drop the material and thus through thisconstant agitation each particle is brought into intimate contact withthe heated shell and the stream of preheated air, which will behereinafter explained, many times during its passage through themachine, thus resulting in a uniformly dried product. As may be readilyseen by controlling the ratio of speed of the drive mechanism 5 to thepitch of the spiral flights 20 any desired speed of travel of thematerial through the drier shell may be attained.

The present type of cylinder, as disclosed in the drawings, is providedwith two heating furnaces or units 2| and 22, which in the presentinstance are of the gas fired type. An important feature the machine.

of the invention is the utilization of the heat from these heatingunitscor furnaces at a predetermined degree or ratio of heat to themoisture content of the material being sent through the machine properfor purposes of being dried. eferring particularly to Figures 1 and 2 ofhe drawings, which are representative of the two halves of the machine,I have provided a gas and heat control apparatus 23 at the feed end ofthe machine and 24 at the discharge end. The control mechanism indicatedat 23 is for the purpose of controlling the temperature of the heatdirected against the drier shell member 2 at the feed end of themachine, whereas the heat control mechanism indicated at 24 is for thepurpose of controlling at a predetermined temperature the heat directedagainst the drier shell 2 from the furnace structure indicated at 22 atthe discharge end of the machine. These. two heating elements or gasfurnaces are separated one from the other by means of the heat chamberdividing plate 25, see Figure 5, thus enabling the complete separationof the furnaces 2| and 22 for the purpose of enabling two separate andindependent degrees of heat to be directed against different portions ofthe drier shell at the same time.

The separate and independent predetermined degrees of heat derived fromthe furnaces 2| and 22 are thermostatically controlled by the thermostatmembers 26 and 21 of the furnace control mechanism 23 and 24,respectively. These thermostats are mounted at the upper or top portionof the drier housing at 28 and 29, respectively, of the feed anddischarge ends of The gas or hot air passages 30 and 3| formed by theupright columns 32 and 33, in which the thermostats 26 and 21 arepositioned respectively, are so arranged as to enable substantially allof the hot air and burned gases derived from the furnaces 2| and 22 topass through the passages 30 and 3|, provided for the furnaces 2| and22, respectively. The hot air and burned gases passing through thepassages 30 and 3| are directed in turn through the air heating chambers34 and 35, respectively, thence by means of the upright passages 36 and31 to a common outlet or cylindrical passage 38 formed by the common gasand hot air discharge pipe 39.

The purpose of the two separate and independent furnaces 2i and 22,which may be readily seen, enables the use of a high initial degree ofheat at the feed end of the drier shell where the material that isintroduced into the drier has its maximum degree of moisture content.Thus for purposes of expediting the drying operation an initial highdegree of heat may be introduced at this point without running the riskof either scorching or burning .the material being dried. It isunderstood that as the moisture content of the material is driven out ofthe same, particularly in the vicinity of the discharge end of the driershell, it is important that the initial degree of heat be lessened tothe desired amount so that the final drying out of the material can bedone without the possibilities of either burning or scorching thematerial. This may be readily done in the present type ofstructure dueto my dual heating feature in that a high initial degree of controlledheat may be introduced to the wet material at the feed end of themachine and a low degree of heat introduced to the material being driedat the discharge end of the machine where the moisture content of thematerial is very low,

by means of my two separate and independently operated and controlledheating furnaces 2| and 22.

With this present type of structure, it should be understood that widevariations of the application of the drying heat or heats may be possible, such as, when using two independent heating furnaces for a givendrying operation, the wet material may have an initial low degree ofheat introduced thereto for the first operation, then a very high degreeof heat applied thereto for the final drying operation. Still othervariations of the drying operation may be had by using three heatingfurnaces, such as introducing the wet or moisture laden material to aninitial degree of high heat, then a somewhat lower degree of heat, thena' final drying heat of a high degree, or this combination of variousdegrees of heat may be changed at will to suit the conditionsencountered, such as, the first or initial heat may be a low degree, thesecond heat may be a high degree, and the final heat may be a low degreeagain. Thus it may be seen, any

variation of drying heats and combinations thereof is possible with thepresent type of drier.

For purposes of introducing a continuous supply of preheated fresh airunder a forced draft, I have provided the blower fan member |5.. Theforced air or draft from this blower member is directed through thepiping 40, as shown in Figure 1, thence through the battery of airheating tubes 4| and 42 positioned respectively in the air heatingchambers 34 and 35, thence to the discharge end or opening of the driercylinder 2 by means of the horizontal cylindrical air passage 43 and thevertical piping member 44 connecting the same to the discharge header ofthe drier proper. This preheated fresh air is thence passed through thedrier shell in the direction indicated by the arrows 45, which is theopposite direction to-the feed of the material being directed throughthe machine to the feed end 46 of the drier shell, thence by way of theupright pipe member 41 to a common discharge pipe 48, which in turn isalso used for purposes of dis charging the hot air and unburned gasesemanating from the furnaces 2| and 22 after they have served theirpurpose of preheating the incoming forced draft of fresh air.

If it is found desirable the fresh air introduced into the shell member2 may be introduced in such a manner as to cause the same to move in thedirection of the traverse of the material being dried.

It will be noted, particularly in Figure 1, that the gas and hot airdischarge pipe 39 has its discharge end 49 positioned at a point inadvance of the passage or pipe 41 for the moisture laden air coming fromthe drier shell. This design of structure is specifically for thepurpose of enabling the hot air or gases in their effort to escapethrough the discharge pipe 48, which in turn leads directly to theatmosphere to create a vacuum which enables the ready discharge of themoisture laden air that may be discharged from the pipe member 41 intothe piping 48. This structure also serves another purpose in that thesame enables the thorough intermingling of the -hot gases with thevaporized or moisture laden air being discharged in the pipe 48, thuscausing expansion thereto and preventing con- .densation of the moisturecarried inthe discharged air from the material being dried, enabling thesame to be wholly discharged into the atmosphere without precipitationof the moisture carried therein.

Referring to Figure 5, it will be seen that the two sets or batteries ofair heating tubes 4| and 42 are each in turn provided with headers 50and 5|, respectively, which in turn form the hot air or gas chambers 34and 35, also enabling the entire blocking off of the hot air or burnedgases passing through the same from intermingling with the incomingforced draft of the fresh air passing through the horizontal cylindricalshaped member 52. As may be seen from Figure 5, the preheating of theforced draft of the fresh air passing through the two sets or batteriesof air heating tubes 4| and 42, which in turn are heated by the hot airor gases emanating from the furnaces 2| and 22, respectively, maybepreheated to a degree of heat which would be determined by the meantemperatures of the hot gases impinging on the two thermostat members 26and 21 of the furnaces 2| and 22, respectively.

It has been found from long experience, particularly in drying tobacco,that unless the temperature of the heating medium used for purposes ofcarrying away a portion of the moisture content of the tobacco iscontrolled to a predetermined degree of temperature proportionate to themoisture content of the tobacco being dried, that the same will bedeprived of its sweet flavor due to its not having its natural moisturecontent.

The natural or sweet flavor that is found in good tobacco is largelydependent on the manner in which the same is dried. When excessive heatis used and particularly without proper control of the same, the naturalmoisture of the tobacco is carried away causing the same to become driedand to lose its freshness and natural sweet flavor.

Referring to Figure 9 of the drawings, I have shown a cross sectionalview of the manner in which the drier shell 2 and the drier housing lare so related at the point where the housing of the drier terminates inrelation to the drier shell 2 for purposes of preventing the readyescape of the hot gases from the furnaces 2| and 22 at either the feedor discharge end of the drier shell. The drier housing carries at eachend thereof, end plates 53 and 54, which in turn may be fixed thereto bywelding or the like, as shown at 55 in Figure 9. The portion of thehousing and end plate 53, that is in juxtaposition to the drier shell 2,has an inwardly directed flange member 56, which in turn may be weldedto the end plate, as shown at 5T. Overlapping and concentrically relatedto the end plate flange 56, I have provided a circumferential flange 58,which in turn is integrally mounted on the drier shell member 2, bymeans of the bolts 59 and circumferential angle iron 65, which in turnmay be fixed to the outer surface of the drier shell by means ofwelding, as shown at 6|.

. As may be readily seen from the drawing in Figure 9, a certain amountof impedance is set up to the ready passage of the hot air or gases fromthat portion of the furnace chambers where the end plates 53 and 54 arein cross relationship with the rotating shell member 2. It has beenfound by experience in actual practice and in the construciion of thepresent invention that the resistance set up by this type of concentricoverlapping non-frictional connection is sufiicient to other in thateach has positioned in juxtaposi- 5 tion-to the underside of the driershell member 2 a battery of gas burners 62 and 53, respectively,together with their respective control mechanisms 23 and 24, forpurposes of enabling the respective batteries of gas burners 62 and 63to be 10 independently controlled as to their degree of temperature heatoutput.

For purposes of supplying the furnaces with the necessary amount of gas,I have provided a main gas supply pipe or connection 64, which 15 inturn has connected thereto the gas supply pipes 65 and 65' for the heatcontrol mechanisms 23 and 24, respectively, which in turn each has gascontrol valves 66 and 66 for purposes of manually controlling themaximum amount of 20 gas that is permitted to reach the burners 62 and63 of their respective furnaces. Referring particularly to Figures 1, 2.and 6, of the drawings, it will be scen that the gas supply pipes 65 and65' each has positioned therein gas flow 25 control diaphragms 61 and61, which in turn are each connected to upright piping members. 68 and68 by means of the piping 69 and 69'. These upright iping members 68 and68' are each in turn connected to the respective gas 30 headers 10 and10' by means of the pipe connections H and H of the respective furnaceheat control elements 23 and 24. These respective gas headers 70 and 10'are each connected by means of the two respective sets of gas burner 35pipes 12 and 12', as shown particularly in Figures 3 and 4 of thedrawings, to the respective batteries of gas burner pipes 13 and 13- ofthe furnaces 2| and 22, respectively. The gas burner pipes 73 and 13'are each provided with a plu- 0 rality of openings 74, at which pointsor openings the gas burner flames are respectively formed.

For purposes of manually fixing the maximum size of the thermostaicallycontrolled flames ofthe gas burner pipes 73 and 13, I have interposedand provided in the gas pipes 12 and 12' the gas valves 74.

Referring particularly to Figures 1, 2, and 6, of the drawings, I haveprovided gas packing joints 75 and 15' in the upright pipe members 68and 68' for the purpose of enabling the manual raising and lowering ofthe respective batteries of gas burner pipes 73 and 13' by enabling themovement or sliding of the respective pipe connections 16 and 15 withintheir gas packing joints 15 and 15'.

The batteries of gas burner pipes 113 and 13' in their respectivefurnaces 2| and 22 are each in turn supported laterally by means ofangle irons 8t and 80', together with their respective slot abutting endmembers 8| and 8|, which may be fixed to the ends of said angle irons bywelding or the like. For purposes of rigidly holding the burner pipes bymeans of their respective supporting angle irons 80 and 80', in fixedrelation to a predetermined position in their respective sets ofpositioning slots 82 and 82', respectively, in the side walls 83 and 84of the furnace or drier housing I have provided the slot engaging bolts85 and 85', respectively, the threaded ends of which may engage the slotabutting end mem- .bers 8| and 8| for purposes of drawing the same tightup against their respective slots for purposes of positioning thebatteries of gas burner pipes.

As may be readily seen by merely loosening up of impinging of the saidflames against the un-.

derside of the drier shell. Upon the determining of the desired size ofthe gas flanies of the various burners and their most favorablepositionin relation to the underside of the drier shell 2, the

heat from said burners and their respective furnaces will be controlledand maintained to the desired temperature required by my heat controlmechanisms 23 and 24, respectively, hereinafter described.

For purposes of admitting air to the respective furnaces 2| and 22 indesired quantities, I have provided each furnace with air inlet dampers86 'and 86', having means for fixing the position of their openings inthe form of segmental slots 81 and 81' with slot engaging butterfly nuts88 and 88, threadedly engaged to bolts 89 and 89', which are integrallymounted on the damper doors 86 and 86. To lessen the fire hazard due tothe heat from the furnaces, I have provided the same with a.closedbottom 90, spaced somewhat away from the fioor proper forming the airspace 9|.

To dispose of any moisture formed by condensation within the gas burnerheaders I and III the same are each provided with drain cocks 92 and92', respectively.

To introduce the necessary amount of air to the respective gas burners,atmospheric mixers 93 and 93 may be provided at the point of entrance totheir respective furnaces of the batteries of gas burners 62 and 63.These mixers may be of the design of any of the well known type ofatmospheric mixers.

For purposes of controlling the amount of air forming the forced draftof hot air passing through the drier, due to external atmosphericconditions, blower fan member I has an air inlet door or damper member94, see Figures 1 and 3 of the drawings, the open and closed position ofwhich may be fixed by the notched bracket 95 to various positions, asshown.

As may be readily seen, particularly from Figures 1 and 2 of thedrawings, each of the heating units or gas fired furnaces 2| and 22 areprovided with heat and gas flow control mechanisms 23 and 24, ashereinbefore referred to, the purpose of which is to enable the heatingof various nortions of the drier shellsimultaneously with differentindependent degrees of controlledii'eat to suit the proportionatemoisture content. of the material being dried as it passes variousdiiferent heat zones during its passage or travel through the driershell 2. This feature as previously pointed out is extremely importantforthe efficient operation of a drier of this character. Particularlywhere tobacco or the like is being dried by having a specific amount ofits moisture content removed by heat without the usual hazards ofburning the material or extracting too much moisture therefrom.

It should be-understood that my invention is of such a'design that anydesired number of independent heat' or gas fired furnaces, each withtheir independent gas flow and heat control mechanisms for purposes ofsupplying various independent degrees of heat simultaneously atvariadvantageously to meet a-particular drying condition efiiciently.

Referring to Figures 1, 2, and 6 of the drawings, the gas fiow and heatcontrol units or mechanisms 23 and 24, each is provided with manuallycontrolled gas pilots I00 and I00, which upon being ignited burncontinuously during the period of operation of the drier as a whole.These gas pilots may be of the well known button valve type, that burncontinuously with a small flame, but upon pressing their quick openingvalve buttons IM and MI an increased flow of gas is immediatelyavailable, thus increasing the size of the pilot flame, the purpose ofwhich will hereinafter be described. The fixed size of both the smalland large pilot flames is controlled by the pilot gas valves I02 and I02in the pilot gas supply pipes I03 and I03 of the furnace control units23 and 24, respectively. These pipes in turn are each respectivelyconnected to the main gas supply pipes 65 and 65'.

The two sets or batteries of gas burner pipes I3 and 13' are eachprovided with master igniting pilots I04 and I04, each of said masterpilots being provided with gas burner openings I05. For purposes ofigniting the master pilots, safety gas pilots I06 and I06 are providedand these pilots are each heat controlled units, the construction ofwhich will. be hereinafter more specifically described. Both of thesesafety pilots are in turn initially actuated and ignited through themanually controlled pilot I00.

An important feature of my invention is the provision of means, whichwill now be fully de-' scribed, for producing a predetermined amount ofheat most desirable for a given specific drying operation. To this endit has been found the provision of my invention for enabling the twobatteries of gas burners to burn continuously at all times during thedrying function of the machine, and to cause the numerous gas flamesfrom said burners to constantly fluctuate from a predetermined maximumsize to a'predetermined minimum size, with said fluctuations underconstant thermostatic control has proven to be a most emcient means ofheat control for driers of the present type.

For purposes of obtaining the above described function I have providedvalves 06 and 60' in the main gas supply lines 65 and 65' for the tworespective gas control structures and furnaces. As may be readily seen,the valves and 66' allow for the control of what may be termed themaximum flow of gas to the furnace heating units. Thus the degree ofopening of these valves when the drier is operating is representative ofthe maximum flame from the batteries of gas burners within the furnaces.However for purposes of controlling this maximum fiow of gas to eachindividual gas burner pipe which goes to make up the batteries of gasburners, I have provided the individual gas control valves 14', ashereinbefore described. These valves, see particularly Figures 3 and 8of the drawings, may also be used to completely shut off the supply ofgas to any one of the burner pipes, thus enabling the furnaces tooperate with any desired number of burner pipes functioning for-purposesof producing the desired amount of heat, by controlling themaximumheight of the flames produced by any particular burner pipe. As it. issomewhat impractical to maintain a predetermined substantially fixeddegree of heat in any of the gas fired furnaces used in the presentinstance, I have found it necessary to provide means, as hereinbeforereferred to, to

cause these maximum gas burner flames to be automatically reduced to apredetermined minimum height or size. Thus reducing the temperatures ofthe various furnaces used herein, and maintaining a constant control ofthe various heats at all times. To this end I have provided minimum andmaximum gas control diaphragm valves for the respective gas furnacesshown, indicated at I I0 and H0 for the minimum gas flow and III and I II' for the maximum gas flow. The maximum gas flow diaphragm valves IIIand III are each in turn controlled by thermostat units 26 and 21 in therespective furnaces. These units are positioned in the heat air passages28 and 23, and each in turn are connected to the maximum gas flowdiaphragm valves I I I and I I I' by the tubing H4 and H4, respectively.The other lines of tubing H5 and H5 connected to the thermostatic unitsas at H2 and H2, respectively, are each in turn connected to both theminimum gas flow diaphragm valves III, III, and the pilots I06 and I06,as shown. The purpose and function of which will be hereinafterdescribed.

Referring particularly to Figure 10 of the drawings, it will be notedthat the thermostatic tubing II 4 and H5 are connected to the upperchambers I I6 and III of the minimum and maximum diaphragm valves II 0and III. For purposes of illustration the valves H0 and III only areshown in detail and will be described as the other valves H0 and III'are similar in structure and function. The upper chambers I I6 and IIIare each in turn connected to the gas supply by way of the piping 65 bymeans of the openings H8 and H9 in the diaphragm valves I20 and I2I.These diaphragm valves function in a manner to control the minimum andmaximum flow of gas to the burners, by way of the openings I22 and I23,respectively. The minimum gas flow control diaphragm valves H0 and H0also control the flow of gas to the master burner pilots I04 and I 04'by way of the piping I24, I24, and I25 and I25, respectively. The valvesI26 and I26, in the gas line pipes I25 and I25, control the minimum flowof gas to the burners, and thus allow for determining the size of theminimum gas burner flame. The gas lines I25 and I25 are each connectedto the maximum gas flow lines 59 and 69, as shown.

The gas tubing H4, H5, H4, and H5 are connected to the minimum andmaximum diaphragm control valves as shown, and are connected at theiropposite ends to the thermostats 25 and 21, respectively. As both of thepresent described thermostatic controls are similar in construction onlythe thermostat referred to by reference numeral 26 will be described indetail.

Referring to Figure 12 in the drawings, in which a cross section ofthermostatic control unit 26 is shown, it will be seen that the gastubing H4 and H5 are connected thereto, H4 to the chamber I30 formedabove the valve member I3I and tubing I I5 connected to the chamber I32formed beneath the valve member I3I. For purposes of closing the valveI3I and holding the same against the seat I33, i. e., in closedposition, a compression coil spring I34 is provided. The valve stem I35,which is fixed at one end to the valve I3I at I36, and is in constantengagement at its opposite end I45 to a carbon rod member I3'I, asshown. The carbon rod I3'I in turn is slidably supported in theadjustable collar shaped member I31 at I38. Carried and integrallyengaged to the collar member I3I at I39, and fully enclosing the carbonrod, is a cylindrical shaped member I40, closed at its opposite end I4I,which in turn engages the end I42 of the carbon rod I31. The cylindricalshaped member or shell I40 is preferably made of any of the well knownmetals that readily respond, in the form of expansion and contraction,to the influences of heat and cold. The length of the carbon rod I3'I issufficient at all times to maintain the valve I 3I in open position aslong as the thermostat shell member I40 remains at a predetermined lowdegree of temperature. For this reason it may be readily understood thatthe valve I3I is constantly raised from its seat I33 during normalheating of the thermostat shell. However as soon as the shell member isintroduced to an excessive amount of heat which by way of illustrationin the present instance, is over and above the predetermined degree ofheat desired, the thermostat shell member I40 is immediately caused toexpand, particularly as to the present design of shell member, in adirection parallel with its axis. Thus allowing for the carbon rod,which is substantially unresponsive to the, heat action in the presentcase, to move away from the valve stem at I45 due to the outwardmovement of the end I 4| of the shell I40. This thermostatic actioncauses the valve I 3| to close and shuts off the circulation of gaspassing through the thermostatic valve structure 26 by Way of the tubeH4, valve chambers I30 and I32, and thence through the tubing II 5. Thepurpose of which will be hereinafter explained. For purposes ofadjusting the thermostat to function at various degrees of heat, thesame may be provided, as shown, with a handle and bracket member I45 foradvancing or retarding the position of the shell I40 and the carbon rodI3'I therein in relation to the valve structure I3I by means of thethreaded portions I41.

Referring to Figure 11 of the drawings, disclosing a fragmentary crosssectional view of the thermostatic pilot member I06, the same consistsof a cylindrical shell shaped member I48 composed of metal havingsimilar thermostatic qualities as that in the expanding and contractingshell member I40 of the thermostat unit 26. The top I49 of thethermostatic shell I48 is closed, the same carrying a depending rod I50,the lower end of which is tapered at I 5| and acts as a valve againstthe valve seat I52. formed in the opening I53, which in turn receives asupply of gas through the pipe and connection H5". I48 is fixed to theextension I 55, as shown, of the-base portion of the pilot I06. Pilotburner openings I56 are provided in the shell, the same being sopositioned as to cause the ignition of gas flowing through the masterpilot member I04 by way of its openings I05. The safety pilot I06, whenthe drier is not operating and the pilot is cool, is to be normallyclosed. However upon operation of the drier, this safety pilot memberThe lower end I54 of the shell contracted position thus lowering theposition of the valve I5I to closed position against .its seat I52. Forpurposes of causing this safety pilot to ignite it is necessary topreheat the thermostatic functioning shell member I48 bybecomes ignitedat the burner openings I56, thus allowing for the ignition of the masterpilot I04 upon the introduction of gas thereto. As may be readily seen,the safety'pilot I06, will upon its initial preheating and lightingremain in an open position and burn continuously due to its own burnerheat keeping the shell suflicientlyhot to hold the valve I5I in openposition. Should the gas flames fromthe safety pilot be inadvertentlyblown or put out or the gas supply thereto shut off from its originalsource, the safety pilot will become cool and close permanently untilthe same is preheated again. The importance of this feature incombination with my structure and invention will be fully describedhereinafter.

The operation of my invention of improved rotary drier, together withthe various steps necessary to be taken to initially start my machinewill now be described, with particular reference being made to Figures1, 2, 6, 8, 10, 11 and 12, of the drawings.

For descriptive purposes, the gas flow control mechanism at the feed endof the-machine indicated-by reference numeral 23;. only will bedescribed in detail as to initial starting, and functioning of thecontrol valves, etc.; as that portion of the-drier furnace, its gas flowand heat controlmechanism indicated by reference numeral 24 at thedischarge end of the machine, is substantially similar in structure andoperation as that shown at the feed end of the machine, and which is nowto be described indetail as to the co-rel'ated'functioning of thevarious units involved in controlling the heat, flow of gas, etc., forthe complete furnace structure at the feed and of the machine.

To initially start the machine or drier, it is preferable to have'thecylindrical drying shell 2 revolving, the first battery of gas burnersindicated at 62 are positioned at a predetermined distance from theshell 2, as shown, the thermostat 26 is then set at a point to give themaximum amount of heat desired, valves 66, I4, I26, and IE2 are set toclosed position, gas cock I02 in the gas line I03 for the preheating gaspilot I is then turned to on position, the pilot I00 is then ignited,this may be more readily done by pressing on the push button of thequick acting push button valve IOI. The flame from this pilot, uponoperating the push button valve, is caused to become impinged againstthe safety pilot or valve I06, the purpose. of which is to preheat theshell I48 of this pilot and cause the valve I5I within the shell to belifted from its seat, as heretofore described in detail, during thispreheating operation of the safety pilot. the gas supply valve 66 in themain gas line 65 may be opened to a predetermined point, thusintroducing gas to both the minimum and maximum diaphragm valves, H0 andIII, respectively. Due to the" closed position of the gas cook I 52 forthe maximum gas flow diaphragm valve I II this valve II I is caused toremain in closed position, the action and function of which will behereinafter described. The fact that the gas cock I62, together with theinitially closed position of the safety pilot valve I5I also causes theminimum gas flow diaphragm valve I I0 to remain in closed position.However upon the opening of the safety pilot valve I5I, due to thepreheating operation, the minimum gas flow diaphragm valve IIOimmediately opens, causing-a supply of gas to be introduced to thesafety pilot I06 this pilot then becomes ignited and the next operationto initially start the furnace is ready to take place.

Upon the opening of the diaphragm valve H0,

' gas is also immediately introduced by way of piping I24 and I25 to themaster or main pilot I04 through its control valve member IIiI, whichhas previously been opened to a predetermined amount, the pilot burnerI04 then becomes ignited, and burns continuously together with thesafety pilot I06, while the drier is operating.

With the master pilot I04 burning it is safe to open up the gas cocks I4to each of the burner pipes 13. The minimum gas flow control valve- I26in the line I25 may now be opened to the desired amount representativeof the size of flame necessary as the minimum flame. Gas will thenimmediately be introduced to the burner pipes I3, and become ignitedthrough the burning of the master pilot I04. Upon determining the sizeof the minimum flame desired by regulating the valve I26 to a finalfixed position, the maximum gas flow diaphragm valve III may be broughtinto active service by opening the gas cook I02 connected thereto, whichreleases this diaphragm valve and permits gas to flow therethrough.Immediately upon the functioning of this valve the gas burner flamesincrease in size and begin to burn at their maximum rate. These maximumnames may in turn be reduced and fixed at a desired size by varying theopenings in the burner valves I4. The thermostat unit 26 having beenpreviously set to function at a given high degree definitely forpurposes of creating and maintaining a predetermined degree of heat fordrying purposes.

For purposes of placing the furnace structure or apparatus in action,shown at the discharge end of the machine, it is only necessary tosubstantially repeat the same or similar operation for this furnaceapparatus indicated at 22 and 24, by manipulating the various duplicatevalves, cocks and pilots, as hereinbefore described for the furnacestructure at the feed end of the machine or drier.

Referring again to the furnace control mechanism-23 at the feed end ofthe machine, and to Figure 12 of the drawings, it may be readilyunderstood, upon the furnace gases or heat that pass in the vicinity ofthe thermostat unit 20 reaching a given degree of high heat, this valvewhich is normallyjopen will function in a manner as hereinbeforedescribed, by closing its valve member I3I. 1

The closing function of the valve I 3I, as may be seen, causes ablockingoff of the circulation 'of gas through the gas tubing H4 and H5, by

causingthe burner flames toimmediately diminish in size to the minimumflame. The burners will then depend wholly on the diaphragm valve H0 fortheir source of fuel. Upon the thermostat 26 cooling oif the same willfunction as heretofore described, in a manner. as to cause the valve l3|to open, thus releasing the blocking eifect of the as in the tubing! and5. This action in turn releases the gas pressure in the diaphragm valvechamber H1, permitting the diaphragm valve l2! to open, introducing themaximum flow of gas to the burner pipes l3 and causing the burner flamesto immediately increase in size for purposes of producing the maximumamount of desired heat.

Referring to the action of the minimum gas flow diaphragm valve III).This valve responds and functions in a manner similar to itsco-operative diaphragm valve Ill. However this minimum gas flowdiaphragm valve responds by automatically cutting off the passage of gastherethrough only when the flow of gas through the tubing 5 and H5" isblocked oh. This may be brought about in the present instance by thesafety pilot I 06 being inadvertently put out, causing the same to coolofl', and as heretofore explained, resulting in the closing of the pilotvalve l5l. lhus blocking off the circulation of;gas through the tubing 5and H5" and causing the complete closing of the minimum gas flowdiaphragm valve llli. Simultaneously with this action, the maximum gasflow diaphragm valve III is also caused to close down, as this valveisalso dependent on the flow of gas by. way of the safety pilot beforethe same may finally function, 1. e., to remain in open position. Thusan important safety measure is accomplished. As may be seen, not onlythe burner pipes '13 but the master pilot I04 is also deprived of itsflow of gas. Thus all the gas burner outlets are out 01f from the gassupply, for the safety provision, that when the pilot is relit forpurposes of starting the furnace up again there will be no dangerousaccumulation of gas within the furnace housing to cause an explosionupon the reigniting of the pilots. It is understood the small pilotflame from the preheating pilot I00 could also cause an explosion shouldthe gas accumulate sufliciently to reach this very small flame. Thissource or possibility of gas explosion is also cut off by the action ofthe valve III), III and I5].

It is fully understood, as hereinbefore referred to, that the furnacestructure at the delivery end of the machine, together with its controland safety features, is similar to those just described for the furnacestructure at the feed end of the machine.

I have thus described my invention specifl cally in detail in order thatits nature and operation may be fully understood, however the speciflcterms herein are used descriptively rather than in their limiting senseand the scope of the invention is defined in the claims.

Having thus described my invention, what I claim' as new is:

1. A rotary drier of the class described, having a rotating cylinder,.said drier having dual heating means connected therewith in the form ofa plurality of independently operated and controlled producing furnacesfor purposes of introducing dual heats to said cylinder in asimultaneous manner, the said furnaces being provided with a gasburners, said burners producing gas flames, manually controlled meanscooperative with said heating means for regulating the horizontal planeof said gas burners and the amount of imp n ng of the said flames fromsaid gas burners against the wall of said rotating cylinder, and meansfor controlling the oxygen consumption of said flames.

' 2. A drier of the type described having a rotary cylinder, a pluralityof heat chambers thereunder,

gas burners within each of said chambers for producing heat, means forregulating the distance of said burners from the rotary cylinder of saiddrier for the purpose of controlling the amount the flames from saidburners will impinge upon the rotary cylinder, and means forthermostatically controlling the heat produced in each of said chambersin a manner independent one from the other for the purpose ofintroducing in a simultaneous manner different degrees of heat upon thesaid rotating cylinder at different areas thereof.

3. A rotary drier of the class described, having a rotary cylinder, aplurality of separate and independent heating furnaces thereunder,independently controlled gas burner heating units within each of saidfurnaces, means for conveying the waste gases from each of said furnaceheating units to separate fresh air heating chambers for purposes ofpreheating the said fresh air previous to its being introduced into therotary cylinder of said drier, means within said heating chambers formaintaining complete separation of the fresh air passing therethrough"and the said waste gases within said chambers, means for forced feedingsaid fresh air through and to said air preheating means, and dual meansfor thermostatically controlling the mean temperature of said preheatedfresh air before the introduction of the same into the rotary cylinder.

LOUIS H. ZEUN.

